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From: "H.J. Lu" <hjl.tools@gmail.com>
To: Jan Beulich <jbeulich@suse.com>
Cc: Binutils <binutils@sourceware.org>
Subject: Re: [PATCH 5/7] x86: re-work insn/suffix recognition
Date: Thu, 18 Aug 2022 08:14:52 -0700	[thread overview]
Message-ID: <CAMe9rOoQakP9XcmY843ozC-MEQYpvQdy-aG4CivpVdcwFEt5Jw@mail.gmail.com> (raw)
In-Reply-To: <995353db-27f3-ea60-8e69-32bcc44dfd49@suse.com>

On Wed, Aug 17, 2022 at 11:24 PM Jan Beulich <jbeulich@suse.com> wrote:
>
> On 17.08.2022 22:29, H.J. Lu wrote:
> > On Tue, Aug 16, 2022 at 12:32 AM Jan Beulich <jbeulich@suse.com> wrote:
> >>
> >> x86: re-work insn/suffix recognition
> >>
> >> Having templates with a suffix explicitly present has always been
> >> quirky. Introduce a 2nd matching pass in case the 1st one couldn't find
> >
> > I don't like the second pass.   What problem does it solve?
>
> It addresses the reasons we have various pretty odd (and confusing by
> their mere presence) insn templates which better would never have been
> there. If you have a better suggestion to eliminate those, I'm all ears.
>
> You can also easily see the issues this solves by looking at the
> testsuite changes. Among other things this once again is a matter of
> providing consistent and hence predictable behavior.

Did you mean the error reporting behavior?  I don't think we should add
a second pass just for it.

> Further this sets the stage for the subsequent two changes, which I
> don't think are easily possible without this 2nd pass.

Does it indicate that the second pass is used quite often?

> And finally you've likely spotted that this is actually a reduction in
> code size, first and foremost because the odd maybe_adjust_templates()
> can now go away. Plus I think you realize that the 2nd pass wouldn't
> be engaged in many cases - it requires a template match failure in the
> 1st pass, after all, which isn't going to happen very often.
>
> Jan



--
H.J.

  reply	other threads:[~2022-08-18 15:15 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-16  7:27 [PATCH 0/7] x86: suffix handling changes Jan Beulich
2022-08-16  7:30 ` [PATCH 1/7] x86/Intel: restrict suffix derivation Jan Beulich
2022-08-17 19:19   ` H.J. Lu
2022-08-18  6:07     ` Jan Beulich
2022-08-18 14:46       ` H.J. Lu
2022-08-19  8:19         ` Jan Beulich
2022-08-19 14:23           ` H.J. Lu
2022-08-19 14:49             ` Jan Beulich
2022-08-19 17:00               ` H.J. Lu
2022-08-22  9:34                 ` Jan Beulich
2022-08-22 14:38                   ` H.J. Lu
2022-08-16  7:30 ` [PATCH 2/7] x86: insert "no error" enumerator in i386_error enumeration Jan Beulich
2022-08-17 19:19   ` H.J. Lu
2022-08-16  7:31 ` [PATCH 3/7] x86: move / quiesce pre-386 non-16-bit warning Jan Beulich
2022-08-17 19:21   ` H.J. Lu
2022-08-18  7:21     ` Jan Beulich
2022-08-18 15:30       ` H.J. Lu
2022-08-19  6:13         ` Jan Beulich
2022-08-19 14:18           ` H.J. Lu
2022-08-16  7:32 ` [PATCH 4/7] x86: improve match_template()'s diagnostics Jan Beulich
2022-08-17 20:24   ` H.J. Lu
2022-08-18  6:14     ` Jan Beulich
2022-08-18 14:51       ` H.J. Lu
2022-08-16  7:32 ` [PATCH 5/7] x86: re-work insn/suffix recognition Jan Beulich
2022-08-17 20:29   ` H.J. Lu
2022-08-18  6:24     ` Jan Beulich
2022-08-18 15:14       ` H.J. Lu [this message]
2022-08-19  8:28         ` Jan Beulich
2022-08-23  2:00           ` H.J. Lu
2022-08-26  9:26             ` Jan Beulich
2022-08-26 18:46               ` H.J. Lu
2022-09-06  6:40                 ` Jan Beulich
2022-09-06 21:53                   ` H.J. Lu
2022-09-07  7:17                     ` Jan Beulich
2022-09-26 23:52                       ` H.J. Lu
2022-09-28 12:49                         ` Jan Beulich
2022-09-28 19:33                           ` H.J. Lu
2022-09-29  8:08                             ` Jan Beulich
2022-09-29 16:00                               ` H.J. Lu
2022-09-29 16:06                                 ` Jan Beulich
2022-09-29 16:20                                   ` H.J. Lu
2022-08-16  7:33 ` [PATCH 6/7] x86-64: further re-work insn/suffix recognition to also cover MOVSL Jan Beulich
2022-08-16  7:34 ` [PATCH 7/7] ix86: don't recognize/derive Q suffix in the common case Jan Beulich
2022-08-17 20:36   ` H.J. Lu
2022-08-18  6:29     ` Jan Beulich

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